


Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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093 FXUS62 KCHS 132326 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 726 PM EDT Fri Jun 13 2025 .SYNOPSIS... Atlantic high pressure will build across the Southeast U.S. through the weekend into next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Through Sunset: Radar continues to indicate convection persisting across our area, especially along and near the inland moving sea breeze. SPC Mesoscale Analysis still indicates minimal bulk shear, and effective shear below 20 kt. DCAPE values are generally less than 600 J/kg, while MLCAPE is in the 2,000-2,500 J/kg range. The overall severe threat is low. But we could still have a strong to marginally severe storm where boundary interactions can work to enhance updrafts. Storms are moving at a decent speed, which is limiting rainfall. But expect a brief heavy downpour. Any minor flooding should remain limited to the low-lying and poorly drained areas, or locations where there is some storm training. Tonight: The mid-levels will consist of us being on the western periphery of sub-tropical ridging. At the surface, High pressure will remain over the western Atlantic, with it`s periphery extending into our area. Any remaining convection should dissipate after sunset, followed by a mainly dry overnight for most areas. Though, we can`t rule out a lone shower or two closer to the coast. Lows will remain mild, mainly in the low to mid 70s. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... The synoptic pattern will favor a somewhat elevated risk for showers/tstms through Monday with the region pinned between subtropical high pressure centered offshore of the Southeast U.S. and a mid-level weakness near the lower Mississippi Valley. Scattered to numerous showers/tstms will be at their greatest coverage and intensity during the afternoon and early evening hours with a potential for some activity to linger into the overnights given the warm and humid airmass that is in place. Moderate to locally strong instability will support a risk for a few strong to marginally severe tstms each afternoon with damaging winds, small hail, locally heavy rainfall and frequent cloud-to-ground lightning being the primary hazards. The risk for an isolated severe tstm will be highest where updrafts can become locally enhanced near mesoscale boundary collisions. Highs will warm into the 90s each afternoon with early morning lows cooling in the 70s. It will certainly be hot and humid with afternoon heat indices peaking 100-107, which is below the 108 criteria for a Heat Advisory. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... The subtropical ridge off the Southeast U.S. coast will build west and intensify through much of next week as a hot and humid airmass remains in place. The ridge could limit the convective coverage for much of the period, although it remains to be seen this far out if the capping inversion noted on some guidance will be sufficient to completely curtail convection. Pops were held closely to the 13/13z NBM (mainly chance category) until confidence on how the building ridge will impact the daily thermodynamic profile increases. Afternoon highs will warm into the lower-mid 90s each afternoon with overnight lows only cooling into the 70s. Localized heat indices could get close to the 108 Heat Advisory thresholds at times, so Heat Advisories could be needed at some point if advisory conditions become a bit more widespread. && .AVIATION /23Z FRIDAY THROUGH WEDNESDAY/... 00Z TAFs: While the sea breeze has cleared most the region, still have a bit of lingering convection out there. Should see this diminish quickly near/after sunset, with winds becoming fairly light throughout the overnight period. Otherwise, look for another round of showers and storms to be possible late tomorrow morning through afternoon. Brief reductions in cigs/vsbys may occur under any storm. Extended Aviation Forecast: Brief restrictions are possible each afternoon and evening with typical summertime thunderstorms into early next week. && .MARINE... Tonight: Atlantic High pressure will yield SSE winds this evening, veering to the SSW overnight. Sustained winds should be 10-15 kt. Though, there could be higher gusts along the land/sea interface, especially if nocturnal jetting sets up. Seas should average 2-3 ft within 20 nm and 3-4 ft for the GA waters beyond 20 nm. Saturday through Wednesday: Typical summertime conditions will prevail over the waters with high pressure centered just offshore of the Southeast States. A broad, southerly wind regime can be expected with winds generally averaging 15 kt or less, except a bit higher along the land/sea interface and Charleston Harbor each afternoon with the sea breeze. Seas will remain 4 ft or less through the period. Rip Currents: An easterly swell surge will arrive along the Charleston County beaches Saturday and all remaining beaches for Sunday. This coupled with locally breezy conditions near the afternoon sea breeze will support a moderate rip current risk for the Charleston County beaches Saturday and for all beaches Sunday. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM... LONG TERM... AVIATION...SST MARINE...